Modern Proposed · Proposed Solar
International Fixed Calendar
The International Fixed Calendar sought regularity and month-to-month symmetry but was never adopted as the global civil standard.
What is the International Fixed Calendar?
The International Fixed Calendar sought regularity and month-to-month symmetry but was never adopted as the global civil standard.
How the calendar is structured
13 equal months of 28 days plus one or two extra days outside the weekly cycle.
13 equal months of 28 days plus one or two extra days outside the weekly cycle.
Where and why it is used
Region: International proposal. Primary context: Calendar reform history and proposal studies.
History and development
The system belongs to the Modern Proposed layer of the archive. Its origin is summarized as 19th–20th century reform movement. CalculatorWiser separates historical reconstruction, religious observance, civil use, and modern technical standards so different systems are not treated as though they all work the same way.
Visual reference gallery
Conversion and accuracy notes
Some calendar systems can be converted deterministically with modern algorithms. Others depend on observation, local authority, historical reconstruction, or regional practice. CalculatorWiser marks those distinctions rather than presenting uncertain dates as exact.
Research trail
This entry is part of the research-backed World Calendar Archive. Primary research anchor for this entry: Calendar reform references.
Related calendar systems
Save to Pinterest